1. Field of the Invention
This invention relates to an apparatus and method for measuring the peel strength of a paper joint which is adhesively bonded. Such structures of this type, generally, allow the peel strength of the adhesively bonded joint to be accurately and repeatably measured in an inexpensive manner.
2. Description of the Related Art
It is known, in adhesive bond testing systems, to make use of a device which tests the tensile strength of the adhesive bond. Exemplary of such prior art tensile testing systems are U. S. Pat. Nos. 4,893,513 to Schroeder et al. and 5,201,230 to Sakakibara. While these tensile testers are capable of measuring the tensile strength required to pull apart an adhesive bond, these testers do not adequately measure the strength applied to "peel" apart the paper members which are adhered together by the bond. It is important to know the "peel" strength of the bond in order to more adequately determine the strength of the bond between the adhered paper members. Also, these testers are prohibitively expensive due to the complexity of their construction. Therefore, a more advantageous adhesive bond testing system would be one which inexpensively measures the peel strength instead of the tensile strength.
It is also known, in glue bond testing systems, to make use of a peel strength tester. Exemplary of such peel strength testers are U. S. Pat. Nos. 3,850,033 to Schmitt and 4,080,825 to Liebrenz et al. While these peel strength testers measure the peel strength of a glue bond, these testers employ motors. Consequently, the system is only as reliable as the motor. If the motor fails, then the system cannot be operated. Also, these testers are prohibitively expensive due to the complexity of their construction. Therefore, a still further advantageous glue bond tester would be one which can inexpensively test the peel strength of the glue bond while avoiding the use of a motorized tester.
It is apparent from the above that there exists a need in the art for an adhesive bond tester which is inexpensive through simplicity of parts and uniqueness of structure and which is capable of measuring the peel strength of the adhesive bond, but at the same time avoids the use of a motorized system. It is the purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.